Jul 31, 2007

Boeing 717

The aircraft currently carrying the Boeing 717 moniker, started out as a DC-9 - descendant of the airliner that started it all, the venerable DC-3. To see the lineage from the 3 to the 9, you only have to compare these flight deck photos:

The DC 3

The DC 9

Here's some early excitement as the original "regional jet" was unvieled:

How this aircraft became the Boeing 717 is told on this Wikki Encyclopedia page. Not surprisingly the 717 is no longer in production - it was a direct competitor to the B737.

I flew a few thousand hours on the DC-9 and that's where I truly learned instrument flying. A typical day's work could include early morning landings in the maritime fog and rain, shooting NDB approaches beyond the radar coverage of the nearest ATC unit ("... You're cleared for an approach. Call the FSS and tell them which runway you'll be using...") and then in the afternoon skipping down to Boston or New York ( ".... turn left to heading 180 degrees. Maintain seven thousand feet. Reduce now to 210 knots. You're number 6 on the approach, call the tower at the XYZ beacon....").

It was a very versatile aircraft but the flight deck was certainly not 'refined' by any stretch of the imagination. As new technology was added, holes were carved out in panels or anywhere else accessible and the new gear stuffed in. Later models showed some evidence of a cleaner design, but it was still a piecemeal approach.

By contrast, the Boeing flight decks revealed more careful design from the beginning - and it just keeps getting better. Compare the two flight deck photos on this Wikki page:

As a matter of trivia - the 717 moniker was originally reserved for a military derivative of the 707 but the number was later released to the commercial jet division.

Jul 30, 2007

Boeing 707 - Pioneering the Jet Age

In considering my own choice in the current poll question (sidebar), I did a little research on the Boeing 707. This aircraft, along with the Comet and early DC-8 pioneered the new era of Jet Transport flying. Today we take for granted the smoothness of jet engines, but to a frequent traveller who'd been subjected to the noise and vibrations of four huge propellors for hour after hour across the ocean, what a treat it must have been. Today the claims of "living room sound and comfort" seem exaggerated but by comparison to the previous era of DC-6 and 7s and Super Constellations, it must have been a treat.

Pan Am Promo:

Adding to the comfort and mystic of jet travel were the parallel advances in technology. Just being able to fly into the tropopause increased the smoothness of the flight as now travellers were above much of the turbulence in the lower airmass. Then the speed of travel - almost the speed of sound! - not only seemed adventurous but chopped route times by half. Along with these innovations came new navigation computers that provided the possibility of direct routes, polar routes, and minimum time tracks that used the best route according to the winds.

And as a testament to how strongly these grand ole aircraft were made - a look at the last years of a Pan Am aircraft still going strong not long ago:

And a test flight that went a "little outside the envelope..."

Fianlly, compared to the airliners of the 21st century, the 707 must have been a real "pilot's airplane." No auto-landings, and very little auto-anything! Grab on and fly folks!

Jul 27, 2007

Boeing, Boeing, Boeing!

Recently Boeing lined up their famous family of airliners on one taxiway. The B707 landed at 7:07, followed by the B717 at 7:17, etc... Neat idea. This got me wondering... Which of these aircraft would I love most to fly for a day of fun and frolicking in the skies? All incidental expenses like fuel, airport fees and so on, included of course!

Personally, I'm vacillating between the good ole' twenty-seven and the Jumbo 747 - I've never flown with 4 engines... Mind you the classic 707 represents the glory days when Jet Planes were a new thing and airline flying was a thrill, not merely a lo-cost commodity. On the other hand, it would be fun to get my hands on that jumbo triple seven. But wait, maybe I'd wait and try the spanking new 787 ... so hard to choose.

How about you? I've added a Poll (check the sidebar) so you can choose your favorite. Also, please post a comment and tell us why. Let's see which airplane wins the TWSO "I want it, I want it, I want it" award!

Jul 21, 2007

Minimum Equipment List - MEL

The recent accident at Sao Paulo, Brazil, apparently involved an aircraft with a deactivated reverse thrust system.

Below is a typical MEL (Minimum Equipment List) page related to the Reverse Thrust system. These manuals are produced in a generic form by the aircraft manufacturers, then each aviation authority and airline within that aviation authority's jurisdiction might add restrictions specific to their concerns. This sample is from the British CAA's version for the Boeing 737-100 airplane (simply because that's the first one I found in an online format).

I don't recall if the Airbus A319 MEL has the same restriction against operations on slippery and flooded runways, but I strongly suspect it does (does anyone have a copy handy out there, to confirm or deny this?)...

I do know that the 319 has great short field landing capabilities with just the normal brakes, anti-skid system and ground spoilers. In fact when executing a max performance (short field) landing on the A319 on a DRY runway, the airplane decelerates so quickly that the reversers can't deploy fast enough to be of much use. That is, by the time the reverse 'kicks in' the airplane is below the minimum speed at which reverse thrust is effective.

I also know that hydro-planning will occur on a runway that has even a small amount of standing water. Once hydroplaning begins, the landing distance tables go out the window. In these conditions, reverse thrust is essential to slowing the airplane until the wheels can contact the pavement.

(click on the image for a full-size view)

Jul 19, 2007

Parachutes vs. Thunderstorms!

Many years ago in a book all about fantastic weather events, I recall reading of a world war II pilot who bailed out of a stricken aircraft at high altitude and had the misfortune to be swallowed up by a thunderstorm. For the next 30 minutes and more he was violently tossed about, soaked by rain and battered by hail and at times tumbled into his collapsed chute. He was sure he would die as the storm alternately lifted and plunged him through thousands of feet of altitude. But finally he did land and lived to tell the tale.

That was the only such case I've ever heard of until now. I just read this incredible story about two para-glider pilots who were drawn up into a severe thunderstorm. One survived to tell the tale, but the other not fare so well:

Soaring Student: Beware of Thunderstorms

Jul 18, 2007

A Day in the Life (27) Ready…

A description of a typical day's flight from Montreal to Vancouver and return - as a backdrop for a detailed, non-technical description of what an airline pilot does. (check left hand column for series index).

Log Entry 2003 - A320 Capt - nearing TOD (Top of Descent)

Time: CYVR Arrival minus 0H45M

With Vancouver in view on our navigation screen, FO Paula decides it’s time for her official briefing. Once she sees I have my charts out and I am ready to follow along, she launches into the prescribed litany, telling me all about the descent, the crossing restrictions, the landing configuration she’s planning and so on.

I dutifully check that the trolls have all been assigned their appropriate parts to play, poking Macdoo with any needed numbers as I go. When all is entered to my satisfaction, I let her know and she finishes up the briefing as she double-checks my work.

Some of the considerations that go into our descent planning:

Wind— we start the descent later against a headwind and earlier with a tailwind. The part that’s hard to know is whether the wind will persist all the way down or will change significantly as soon as we leave cruise altitude.

Landing weight — we start the descent further away when we are heavy and closer when we are light.

Crossing restrictions - most busy airports have defined arrival paths that require us to hit certain navigation points at specific altitudes and speeds. These usually force us down earlier than we’d like, then require us to add power and ‘drag’ the airplane along level again until the next descent stage. This is necessary to interweave us with traffic outbound or landing at nearby airports.

Anti-icing requirements - if we need to keep the engines and maybe even the wings heated in descent to prevent ice forming, we need to start the descent earlier. The engines provide the hot compressed 'bleed air' for this job, so we have to run them at higher than idle power - effectively lengthening our descent distance.

Descent Speed - If we are running late and plan to use a higher descent speed to gain time, we will begin the descent closer to the destination. Higher airspeed means more aerodynamic drag which gives a steeper descent. But with the price of fuel the way it is, we don’t do this as much as we used to. It’s more economical to start the descent earlier and glide down at a lower speed which trades more forward distance for altitude.

In an ideal setting we close our engines to idle power at the top of the descent, and keep them like that all the way to the final approach alignment with the runway. If our calculations prove to be off a little we can compensate by adjusting our airspeed. Dive faster to get down sooner, or reduce our airspeed to glide further. If this isn’t enough, then we extend the speed brakes to add more drag and descend more steeply, or in the other case, we open the throttles to add engine power.

It’s a sweet feeling to glide all the way down from say thirty or forty thousand feet slowing down at the appropriate times, extending the flaps and landing gear at just the right times, and then applying engine power for only the last few minutes to lock in our final approach speed to the runway.

Every pilot has their own “special” formula for working out all these variables to come up with the most accurate descent point. But a quick and simple rule of thumb is to take three times the cruise altitude in thousands of feet and use that as the miles to fly to landing.

So if we are landing at Vancouver (sea level) and we’re at 39,000 feet like today, three times thirty nine gives us 117 flight path miles to touchdown. To this we add and subtract adjustments for the factors I just mentioned. Before the use of flight management computers which include vertical navigation guidance, it was a point of pride for pilots to come up with the best possible estimate.

With the Auto-Bus we give Macdoo the forecast winds for the descent, along with any required crossing restrictions, and then sit back and watch the Genies come up with a descent point. But again the old computer adage “garbage in, garbage out” applies. If the guidance system has an inaccurate lateral path in the program, then of course the vertical path will be wrong.

Also, the automation needs careful watching during descent. Especially if the winds are different than forecast. I’ve seen it happen many times where the navigation Spirits will show us a GREEN number at a key crossing restriction which means “I’m gonna make it…”, only to have it turn AMBER at the last moment which is the computer equivalent of throwing hands in the air shouting, “I'm not gonna make it! I'm not gonna make it! Do something!”

Today, FO Paula finishes up her briefing by reviewing the crossing restrictions and other data I’ve entered. When she gets to the descent speed item she pauses to ask if I’m interested in a higher-than-normal descent speed to try to improve our gate arrival time. I am. She taps in a number just ten knots below the redline limit. She then finishes the briefing and I ensure she knows how and when we’ll transfer control after landing.

Finally she calls for the “pre-descent checklist” and I pull out the metal card. Following the script again, I perform the final confirmation:

“Approach Briefing; Completed.
Landing Data; Set.
Pressurization; Checked.
ECAM Status; Checked.
Nav Accuracy; Checked.
Pre-descent checklist complete.”

The entire procedure flows smoothly and includes important cross-checks of crucial data, and it took us many hours of hard work to make it look this easy.

But that's it. We’re set.

Time: CYVR Arrival minus 0H30

Jul 16, 2007

A Day in the Life (26) Land Ho!

A description of a typical day's flight from Montreal to Vancouver and back - as a backdrop for a detailed, non-technical description of what an airline pilot does. (check left hand column for series index).

Log Entry 2003 - A320 Capt - Cruise

Time: CYVR Arrival minus 1H00M

Land Ho!

How exciting those words must have once been to a weary sailor. I can only imagine what it meant for them, after months and months at sea, to espy dry land and the promise of a safe conclusion to a dangerous voyage. Today, I've only been airborne six hours yet I’m exhilarated to see the CYVR tag finally crawl over the top edge of our electronic horizon, with its promise of nothing more than a quick stretch of my legs and a stale airport deli sandwich.

The activity level steadily increases as FO Paula and I stow items prior to descent, and generally clean up the flight deck. “A tidy flight deck is a happy flight deck.” some old captain used to chant at me at least once each trip. Now I can’t get it out of my head. I try not to inflict it on my first officers so I don't say it out loud - at least not more than once per trip.

I’m sure I have other oft-repeated phrases and habits that drive my first officers crazy. It's expected. It's part of the mystic of being an "Experienced" Captain. It's part of 'the deal.' My first officers tolerate my irritating, repetitive behaviors hoping that there may actually be some good reasons behind them. And if I actually remember some good reason that led to a particular 'irritating behavior' I endeavor to retell it at least once each flight. Oh, wait. I guess that's how these irritating behaviors develop. Which reminds me of a story... (but I digress and that's another entry for another day.)

The flight deck procedures specify that the PNF (pilot not flying) will program the waypoints and approaches and frequencies into our flight management computers for the arrival, but in reality, during a long segment the initial entries are entered by whichever pilot needs a pastime enroute to help stay awake. I’ve tapped in some rough numbers long ago. From time-to-time FO Paula has updated these as new weather reports came in. I now pull up the official ATIS report for Vancouver and enter a more detailed plan of our expected approach.

From this I derive a better gate arrival estimate which I send to the company. They need to utilize their resources of gate space, ground support equipment and personnel efficiently. Especially when we're behind schedule. I also make a final announcement to the passengers. Vancouver weather is improving steadily and it seems like the December rains have fled for a while, tantalizing us with the prospect of a mountain vista during the descent, along with probable turbulence below twenty five thousand feet, judging by the clouds I see out the front windows. The airport winds are light and favoring a straight in approach from the east, landing on Runway 26 right. We should regain a couple more minutes on our arrival time.

I gather some snack dishes to return to the galley and my bladder needs another break as well, so I push the call button and talk with Connie to initiate the PPP (Pilot Peeing Protocol). Curse you Osama! I’m the only person I know who needs a body-guard to take a whiz. Well, okay. There's me and a few thousand other airline pilots around the world...

Time: CYVR Arrival minus 0H45

Jul 13, 2007

Go North!

Going back to that thunderstorm item - here's another strategy that worked well in this case for Air Canada 168. He had the fuel and the clear weather at the end of the storm line to deviate north of course, and land from the east side.

I think he managed to arrive before the 'red alert' began as well. Timing is everything.

Medium Intensity

I've viewed this embedded video a few times. It shows the old "checkerboard" approach into Hong Kong. I've never flown it and now never will because there is an entirely new airport in service, making this procedure obsolete. It was a unique bit of aviation lore. A semi-instrument; semi-visual approach that required a serious turn at low altitude, demanding impeccable judgment and timing from the pilot.

One thing I enjoy about this video, is the music added to the sound track. This music (for me at least) alludes to the required level of intensity in the flight deck. I once read something about how we humans best accomplish complex tasks. The goal, it said, was for us to maintain a Medium Level of Intensity. That is, not too lackadaisical or complacent, but also not overly-intense.

The problem with complacency is obvious, but the problem of over-intensity is less obvious. Every pilot who starts training to fly by instruments soon discovers what the problem looks like. We become so occupied with one part of a complex exercise, we completely forget the other aspects. For example, while trying to correct a heading deviation we stare at the directional instruments, and without realizing it, we drift off our assigned altitude. And the harder we try, the worse it gets and the situation deteriorates. Been there - done that!

At all times during a complex maneuver like landing an airplane, we need to keep the 'supervisor' part of our brain engaged - that part that can overlook the whole problem, then prioritize and act on specific items, yet never lose sight of the big picture. But ironically, when we get too intense, that supervisor brain somehow checks out - unrealized by us of course until it's too late.

So often during difficult conditions, it's good - it's necessary even - to maintain a little humor. To sit back and loosen our choke-hold on the controls. And remember to breath (I'm not exaggerating!).

The professional flight deck atmosphere apparent in this video sets a great example. The pilots are alert, precise and working well together, yet the voices are relaxed and there's even a little laughter heard as the plane exits the runway. All good signs of that desired "medium" level of intensity.

NOW - in contrast to that excellent job, here's another landing on the same runway that probably involved a little too much intensity. If not during, then certainly afterwards as the pilots and passengers raced for the bathroom!

Jul 12, 2007

To Land or Not to Land?

I thought you might like to know something of the different strategies employed by pilots when facing a landing near thunderstorms.

Using this page: and the links to Flight Aware provided there, I was watching the activity at Ottawa airport yesterday as a line of serious thunderstorms moved through. I captured screen snapshots and have compiled them into a short movie embedded below.

(The blue planes are landing or departing from Ottawa but there are sometimes errors. Air Canada 104 is initially shown in blue which is correct. Also for some reason the little airplane icons often point in a nonsensical directions.)

As the video starts notice West Jet 772 in the top left corner. This pilot has decided to hold for a few minutes, knowing that the storm line will soon pass over the airport and this will allow him a clear, safe landing. And probably a smoother ride for the passengers. After a couple turns round the hold, he takes vectors south into a downwind leg for runway 32. Just before the turn back towards the airport he takes a 360 degree turn to help dump excess altitude. Air Canada 104 follows him in along a similar route.

Meanwhile, several flights coming from the east side of the line find their way through a break in the weather and successfully land. The wind during touchdown is 90 degrees across the runway, at 15 gusting to 25 knots. This is within the limitations of most transport and business aircraft, but "challenging." What makes it more challenging is that at the height of the storm there are reports of heavy precipitation and lightning three miles north of the field and later some strikes on both sides of the approach path for runway 32.

Why would the flights from the east side continue in and land during these conditions? Their main problem is that they will have to cross that line of weather sooner or later - it's moving eastward. Some are effectively "racing" against it to land before conditions get too bad at the field. Others, later on, are judging that the ceiling, visibility, rainfall intensity, crosswind and turbulence are within acceptable limits to continue to land.

These are amongst the toughest calls pilots have to make, especially in the dynamic atmosphere surrounding thunderstorms. But, as someone said, "That's why we get paid the big bucks!" Usually we land successfully and all is well. Sometimes an intense rainburst, or downburst of wind or windshear erupts and pilots suddenly have to break off the approach and go-around for another attempt.

Rarely but tragically, a pilot enters weather that exceeds the airplane's capabilities or limitations and a crash occurs. A recent example of this might be the Air France A340 that slid off the far end of the runway in Toronto due to tailwinds, windshear and wet pavement.

I've seen (storm)clouds from both sides now (sorry, couldn't resist), and a few times I've had to 'go around' at the last minute when I lost the race to the runway (more about that another time). The "waiting for the weather to pass" strategy is certainly easier on the nerves, provided you have the fuel for it and you happen to be on the right side. (T-storm lines in North America usually run from west to east, but often with significant northerly or southerly components).

Interestingly, all these flights arrived at the gate at approximately the same time. During storm passage the ramp was shutdown by a "red alert." That is, to protect ground personnel from the dangers of a lightning strike (there have been several deaths over the years), airport staff are required to get off the ramp and seek shelter. So, many flights that beat the storms to the airport, had to sit and wait until the weather passed before the passengers could deplane. It happens.

Jul 10, 2007

Cockpit Conversation: Flight Director

In today's post, Aviatrix relates a story from the "good ole days" when Captain was a term generally synonymous with King - at least in the airline industry.

It reminded me of a similar story:

A new second officer (third pilot crew-member), presumably still on probation, was talking on the intercom to a flight attendant at the back of the cabin regarding some question she had. The S/O made a derogatory reference to the Captain's pedigree during this conversation - something like: "Just a minute, I'll ask the xxxx what he's going to do about that." (perhaps there had already been some personality clashes between this new SO and the Captain in question?)

As it happened, the Captain had his intercom selected ON and overheard the conversation.

The S/O's career was abruptly terminated.

Cockpit Conversation: Flight Director

Jul 8, 2007

Dream Boats of the Sky

The Bel Geddes Airliner no. 4 is a dream-boat of an airliner. It captures an era when aviation was thought of as sailing in an ocean of air -- as something elegant and adventurous rather than utilitarian.

What I find interesting is the similarities between this fantasy aircraft, and that iconic fantasy spacecraft, the U.S.S. Enterprise from Star Trek.

I guess the big airships were as close as we came to this vision of voyaging in the sky. And of course that all came crashing down on that fateful day when the Hindenburg exploded and burned.

Jul 3, 2007

Canada Day Fireworks

On a July 1st evening a few years ago climbing out of Montreal we saw fireworks bursting up from the Old Port area of the city. It was a clear night so just ten minutes later we had an excellent view of more fireworks as we passed Ottawa, the nation's capital. Lesser displays kept popping up from smaller communities across western Quebec and northeast Ontario as we progressed down the airway towards Toronto. The darkened countryside far from big-city lights continually erupted with wiggly blue-white sparks and rainbow trails of silent fiery tribute.

We weren't the only ones to notice. A U.S. flight crew departing Toronto called down on the frequency, asking what the fireworks were for.

"It's our fourth of July," the controller quipped. "We like to get a head start." After a short pause, someone else chimed in to clarify; "It's Canada Day."

"Ah yes. Nice view from here tonight," The American pilot returned. "Happy Canada Day," he added before flipping over to Buffalo center.

It was a unique flight where chance timing coincided with excellent weather to give us a special show. But it was the most fireworks I ever hope to see from the flight deck - if you get my drift.

Jul 1, 2007

To and Fro...

Interesting imagery of air traffic to and from North America over a two day period: